Help with assignment?

[corong1997]

Hi everybody. I just started learning java in my computer science class, and I have to write a program for a lottery. Here is my current code, but I'm getting some issues with my if and else statements. Could somebody tell me what's wrong?

import java.util.Random;

public class Lottery

{

    public static void main(String[] args)
    {
        Random gen = new Random();
        
        System.out.println("Your numbers are:");
        
        System.out.println(gen.nextInt(100));
        int x = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int y = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int z = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int a = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int b = gen.nextInt(100);
        
        System.out.println("The winning numbers");
        
        System.out.println(gen.nextInt(100));
        int c = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int d = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int e = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int f = gen.nextInt(100);
        
        System.out.println(gen.nextInt(100));
        int g = gen.nextInt(100);

        {
        if (x == c)
        {
        int gradea = 1;
        }
        else if (x != c);
        {
        gradea = 0;
        }
    }
        
       {
        if (y == d)
        {
        int gradeb = 1;
        }
        else if (y != d);
        {
        gradeb = 0;
        }
    }
        
       {
        if (z == e)
        {
        int gradec = 1;
        }
        else if (z != e);
        {
        gradec = 0;
        }
    }
        
        {
        if (a == f)
        {
        int graded = 1;
        }
        else if (a != f);
        {
        graded = 0;
        }
    }
        
    {
        if (b == g)
        {
        int gradee = 1;
        }
        else if (b != g);
        {
        gradee = 0;
        }
    }
    
    System.out.println(gradea + gradeb + gradec + graded + gradee);
}

}

[DarrylBurke]

I'm getting some issues with my if and else statements. Could somebody tell me what's wrong?

Not without a crystal ball, no. You need to tell us what those 'issues' are.

db

[corong1997]

The long chunk of System.out.println is fine. Then, when I have my if statements, I try to store the result as an integer, but I get an error next time I try to use it. So for example, when I have

    {
        if (x == c)
        {
        int gradea = 1;
        }
        else if (x != c);
        {
        gradea = 0;
        }
    }

the gradea = 0 pulls up an error, saying "cannot find symbol - gradea". I'm sure there is a super simple fix to this, but I just started and have no idea what is wrong and how to fix it.

[DarrylBurke]

Have you learned about the scope of variables? A variable is visible only in the scope in which it is declared. Which commonly means the immediately surrounding pair of braces { ... }

To use a variable in both an if and an else statement, that variable needs to be declared outside of both.

db

[jim829]

Note: The following is syntactically wrong. Here is a progression of changes that gradually improve the logic.

{

    if (x == c)
    {
    int gradea = 1;
    }
    else if (x != c);
    {
    gradea = 0;
    }
}

First, your 'else if' conditional has a semi-colon right after it. So what you probably want is the following:

{

    if (x == c)
    {
    int gradea = 1;
    }
    else if (x != c)
    {
    gradea = 0;
    }
}

Having said that, you don't need the else if conditional, because if x == c, the only other possibility is that it does not equal c. So do the following:

{

    if (x == c) // if x == c
    {
    int gradea = 1;
    }
    else // x != c
    {
    gradea = 0;
    }
}

Finally, as had already been stated, change the scope of your int declaration.

int gradea = 0;
{
    if (x == c)
    {
        gradea = 1;
    }
}

Now gradea has a default value of 0. So all you need to do is test if x == c to change it.

This does not ensure that the rest of your code is error free or that it will do as you desire.

Regards,
Jim

[JosAH]

Note: The following is syntactically wrong.

.s/syntac/seman/

kind regards,

Jos

[corong1997]

Oh okay, that makes sense. Thanks everybody!

[jim829]

Well duh!! Otherwise, it wouldn't even compile.

Regards,
Jim

[corong1997]

Okay, so I got the int and if statements to work, and I created an input feature in JOption. I'm only running into one bug, and once I fix this, my program will be working great. Basically, sometimes when I input, for example, five 1's, and there are no 1's in the winning numbers, the program will still come up with one or two numbers correct, even though that's not what's showing up in the JOptionPane window. Here is the code. I suspect it has something to do with the lines after the "JOptionPane.showMessageDialog(null, "The winning numbers are");" line, but I'm not totally sure. You guys have all been a huge help, thanks so much!

import java.util.Random;

import javax.swing.JOptionPane;

public class Lottery

{

    public static void main(String[] args)
    {
        Random gen = new Random();
        
        int x = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your first number"));
        
        int y = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your second number"));
        
        int z = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your third number"));
        
        int a = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your fourth number"));
        
        int b = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your fifth number"));
        
        JOptionPane.showMessageDialog(null, "The winning numbers are");
        
       JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int c = gen.nextInt(10);
        
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int d = gen.nextInt(10);
        
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int e = gen.nextInt(10);
               
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int f = gen.nextInt(10);
        
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int g = gen.nextInt(10);
        

            int gradea = 0;
                
                
                    if (x == c)
                
                
                        gradea = 1;
                    
                    
            int gradeb = 0;
            
                
                    if (y == d)
                
                
                    gradeb = 1;
                
                
            int gradec = 0;
            
                
                    if (z == e)
                
                
                    gradec = 1;
                
                
            int graded = 0;
            
                
                    if (a == f)
                
                
                    graded = 1;
                
                
            int gradee = 0;
            
                
                    if (b == g)
                
                
                    gradee = 1;
                
               
                
        int score = gradea + gradeb + gradec + graded + gradee;
        
        JOptionPane.showMessageDialog(null, "You got " + score + "numbers correct");
            }
        }

[gimbal2]

You realize that when you display the random number, you are GENERATING one which you then throw away, and then you generate another one which you assign to the cdefg variables. So what you are seeing in the dialog is not the random number you are actually using.

[corong1997]

Oh, okay that makes a lot of sense. I tried doing an Integer.parseInt like I did when inputting the numbers, but I got an error "'void' type not allowed here". What would be a possible way to generate a number and then store it as an integer?

[Ubiquitous]

Okay, so I got the int and if statements to work, and I created an input feature in JOption. I'm only running into one bug, and once I fix this, my program will be working great. Basically, sometimes when I input, for example, five 1's, and there are no 1's in the winning numbers, the program will still come up with one or two numbers correct, even though that's not what's showing up in the JOptionPane window. Here is the code. I suspect it has something to do with the lines after the "JOptionPane.showMessageDialog(null, "The winning numbers are");" line, but I'm not totally sure. You guys have all been a huge help, thanks so much!

import java.util.Random;

import javax.swing.JOptionPane;

public class Lottery

{

    public static void main(String[] args)
    {
        Random gen = new Random();
        
        int x = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your first number"));
        
        int y = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your second number"));
        
        int z = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your third number"));
        
        int a = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your fourth number"));
        
        int b = Integer.parseInt(JOptionPane.showInputDialog(null, "Pick your fifth number"));
        
        JOptionPane.showMessageDialog(null, "The winning numbers are");
        
       JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int c = gen.nextInt(10);
        
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int d = gen.nextInt(10);
        
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int e = gen.nextInt(10);
               
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int f = gen.nextInt(10);
        
        JOptionPane.showMessageDialog(null, gen.nextInt(10));
        int g = gen.nextInt(10);
        

            int gradea = 0;
                
                
                    if (x == c)
                
                
                        gradea = 1;
                    
                    
            int gradeb = 0;
            
                
                    if (y == d)
                
                
                    gradeb = 1;
                
                
            int gradec = 0;
            
                
                    if (z == e)
                
                
                    gradec = 1;
                
                
            int graded = 0;
            
                
                    if (a == f)
                
                
                    graded = 1;
                
                
            int gradee = 0;
            
                
                    if (b == g)
                
                
                    gradee = 1;
                
               
                
        int score = gradea + gradeb + gradec + graded + gradee;
        
        JOptionPane.showMessageDialog(null, "You got " + score + "numbers correct");
            }
        }

In your code you are already storing the values you are just doing it in a slightly incorrect order.

What your code is doing

// This line is displaying a message box which displays a randomly generated number.
// Since this number is not stored it is thrown away once you close the message box.
JOptionPane.showMessageDialog(null, gen.nextInt(10));

// In this line you are creating an int called 'c' which stores a new randomly generated integer.
// The odds of it being the same as the displayed integer in the previous line is low.
int c = gen.nextInt(10);

As you can see you are already storing them but not until after you already display information that gets thrown out. Think of storing data then displaying.

For example.

// Create scanner object to get user input
Scanner usrInput = new Scanner(System.in);

// Ask user name that can be store into a variable
System.out.print("Hello what is your name? ");

// Store user's input into variable called name
String name =  usrInput.nextLine();

// Display user's name.
System.out.println("Hey! My name is also " + name);

[gimbal2]

Oh, okay that makes a lot of sense. I tried doing an Integer.parseInt like I did when inputting the numbers, but I got an error "'void' type not allowed here". What would be a possible way to generate a number and then store it as an integer?

I have little to add to what Ubiquitous said. Only that you prove just one thing here: you can't get it done by just trying stuff and hoping for the best, you have to understand it first.

[corong1997]

Ah, okay. That makes a lot sense how I was trying to do it backwards rather than store first. Thanks! And gimbal- Learning to program has definitely begun to teach me that. It's really humbling to come onto a forum like this and have so many people willing to help me out, even though the errors I run into are super simple. You guys are awesome

[DarrylBurke]

Right. But before you start your next thread, go through the Forum Rules, especially the third paragraph.

db

[jim829]

It seems to me that in your version of the lottery, order is important, not just choosing the correct numbers. For example, you check

if x == c and
y == d.

What if x = 5 and c = 6
and y = 6 and d = 5?

Did they choose 2 correct or 0 correct? If this is for an assignment, you had better make certain.

Regards,
Jim